He is best known for playing the character Cliff Clavin on the comedy series Cheers, for which he earned two Primetime Emmy nominations.

[1] Through the 1970s, he performed with Ray Hassett as the comedic theatrical duo Sal's Meat Market, which toured throughout Europe for eight years.

[8] Sal's Meat Market heavily influenced Peter Richardson and Nigel Planer as a duo in The Outer Limits and in The Comic Strip.

[10] Ratzenberger also came up with the idea for Cliff's trademark white socks, which he wore as a tribute to French comedian Jacques Tati.

[12][13] Ratzenberger provided the voice for an animated version of Cliff on The Simpsons sixth-season episode "Fear of Flying".

Ratzenberger stated his favorite Pixar role was Hamm from the Toy Story series,[16] and he has given honorable mention to P.T.

[27] Additionally, Ratzenberger provided the voice for Aniyaku the assistant manager in the English dub version of Studio Ghibli’s Spirited Away (2002),[28] which Lasseter also executive-produced.

[32] Ratzenberger developed a packaging-alternatives product made from biodegradable and non-toxic recycled paper as a safe alternative to foam peanuts and plastic bubble wrap.

During the 2008 presidential race, Ratzenberger campaigned for John McCain, appearing with former Cheers co-star Kelsey Grammer at several Republican party events.

[36] On January 17, 2010, he appeared and endorsed Scott Brown for the United States Senate at Mechanics Hall in Worcester, Massachusetts.

[41] During the COVID-19 pandemic, Ratzenberger expressed his support for the United States Postal Service (USPS) in 2020 via Cameo and suggested people who wished to help them donate and buy presents for Christmas early.